"We think China will be stronger if it opens up and liberalizes its own system," the president said.

Obama made the comments during a joint press conference in the East Room of the White House with Japanese Prime Minister Yoshihiko Noda.

As Mark reported earlier, Chen escaped from house arrest earlier this month and unconfirmed reports put him at the U.S. embassy in Beijing.

Obama said he was aware of the reports but that he would not comment.

The press conference is ongoing. We'll update this post with more.

Update at 2:45 p.m. ET. On Bin Laden's Killing:

President Obama was asked about a statement made by Mitt Romney today. Close to the one-year anniversary of the killing of Osama bin Laden, Romney said that "even Jimmy Carter" would have ordered the raid on the Pakistani compound where bin Laden was staying.

President Obama did not address Romney by name but did say that people "should take a look at people's previous statements" and "let them explain it."

Obama was referring to 2007 debate in which Romney is asked directly if he would order a raid in Pakistan to capture bin Laden. Romney gives a nuanced answer in which he says it's wrong for the United States to say they will going into a foreign country unilaterally. Romney seems to imply that saying that is not OK, but that the U.S. could still have that option.

Update at 2:59 p.m. ET. Japan, U.S. Relations:

On the relationship between the United States and Japan, Obama and Prime Minister Noda outlined "a new joint vision" for the two countries.